Rubber shoe sole

ABSTRACT

An environment-conservation rubber shoe sole is made of vegetable fibrous materials including disposed rice/wheat husks, together with natural and synthetic rubbers with suitable amounts of curing additive, activation prompter, and filler, which, after being fully mixed and stirred, are subject to pressurization to form material sheets of suitable thickness for subsequent deposition in a forming mold for curing and molding by heating and pressurizing to complete formation of shoe sole made of environment-conversation material, whereby a de-molded product can be finished with simple trimming whereby low-cost, comfortable, and easy-to-recycle environment-conservation rubber shoe sole can be manufactured and true non-pollution use of shoe sole can be realized.

BACKGROUND OF THE INVENTION

(a) Technical Field of the Invention

The present invention relates to a rubber shoe sole, and in particular to an environment-conservative rubber sole that is made of vegetable fibers, such as rice/wheat husks, which is mixed, with a proper ratio, with natural and/or synthetic rubber, with addition of suitable amounts of curing additives and activation prompters, the mixture being uniformly stirred to provide a raw material that is subject to pressing to form material sheets for easy deposition into a forming mold to carry out in-mold curing and forming by heating and pressurizing to eventually obtain a rubber sole, featuring both continuous and efficient forming of shoe sole and environment conservation to thereby improve wearing comfort and recycling for reuse and reduce costs of shoe sole manufacturing.

-   -   (b) Description of the Prior Art

Materials for making shoe soles, especially outsoles, often comprise a great amount of rubbers for wearing resistance. Since there are only limited resources available in the Earth and also since the natural rubber has various applications with great consumption, modern people are developing conscience of environment protection. To make shoe sole manufacturing complying with the trend of environment conservation with a consideration of environment protection based processing of disposed wastes, reduction of wasting and consumption of the natural resources, and recycling for reuse and regeneration of industrial products, environment protection is now one of the design issues for industrial products or general commodity.

Disposed shoe soles are often handled as wastes. Due to the environment-conservation oriented trend of consumption that has recently developed, shoe soles featuring environment conservation are now available in the market. The conventional environment-conservation shoe soles that are available in the market are made of paper based materials or cork chips mixed materials, which are further mixed with pulps, additives, and adhesives for enhancing hardening and water-resistance. Such materials are then processed by stacking, pulverization, stirring and compression for forming, and trimming to eventually complete shoe sole manufacturing. The portion of the shoe bottom that is in contact with the ground requires sufficient water-resistance and wearing-resistance and is often provided with an additional layer of rigid plastics to complete the manufacturing of the shoe sole. This is a complicated manufacturing process and requires multiple operations and controls before a shoe sole featuring environment conservation can be obtained. As a consequence, the overall manufacturing costs are very high and the rigidity of the sole bottom is proven a very unsatisfactory characteristic for wearing and walking and easy to break.

Thus, to reduce the manufacturing costs of the shoe soles, to provide the shoe soles with satisfactory characteristics of use, and to allow the material that makes the shoe soles to be consumed in a more environment conservative and less expensive manner, the paper based or cork chip based materials that are commonly used in manufacturing environment conservation shoe soles are just not fit for these purposes for they are of limited effectiveness in serving environment conservation for the reasons that pulps or cork chips are products of wood and pulp or paper based materials are obtained from trees, which grow very slowly. Clearly, the effectiveness that can be obtained for environment conservation by using tree material is just limited and the best result of which is simply causing no secondary pollution to the surroundings. It is questionable of the practical effect and protection of environment that using the tree material in an environment protection chain of shoe sole.

Therefore, it is desired and a challenge to the researchers and manufacturers to provide a material for making environment conservation shoe soles that is of low costs, has excellent capability of efficiently forming, and has values of long span effect of environment protection.

SUMMARY OF THE INVENTION

The primary purpose of the present invention is to provide an environment-conservation shoe sole that is made of rubber added with a suitable amount of disposed rice husk material, which are uniformly mixed and stirred for subsequent molding by heating and pressurizing to form the shoe sole whereby the shoe sole so made is of a long span effect of environment conservation and the manufacturing process of the shoe sole is simplified and thus realizing multiple purposes in environment conservation and economics.

In view of the above-discussed drawbacks of the conventional environment-conservation shoe soles of being high costs of material and processing and having no long span effect of environment protection, the present inventor, based on his experience in researching and developing environment-conservation materials and carrying out a series of tests and experiments, has developed an environment-conservation rubber shoe sole, which is comprised of high percentage of recycled waste materials, including rice/wheat husks, mixed with regular rubber. The mixtures is fed into a forming mold and is subject to curing by pressurizing and heating and thereafter, a semi-product is removed and is subject to edge trimming to thereby complete the manufacturing of an environment-conservation shoe sole that features excellent cushioning and lightweight. The shoe sole of the present invention can be manufactured by successively molding so that the manufacturing costs are substantially lowered to thereby overcome the problem of high costs encountered by the conventional environment-conservation shoe soles.

The foregoing object and summary provide only a brief introduction to the present invention. To fully appreciate these and other objects of the present invention as well as the invention itself, all of which will become apparent to those skilled in the art, the following detailed description of the invention and the claims should be read in conjunction with the accompanying drawings. Throughout the specification and drawings identical reference numerals refer to identical or similar parts.

Many other advantages and features of the present invention will become manifest to those versed in the art upon making reference to the detailed description and the accompanying sheets of drawings in which a preferred structural embodiment incorporating the principles of the present invention is shown by way of illustrative example.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a flowchart of a manufacturing method of environment-conservation shoe sole in accordance with the present invention;

FIG. 2 shows a flowchart of a process for stacking the shoe sole of the present invention and a synthetic rubber pad; and

FIG. 3 shows a flowchart of a secondary molding process for the shoe sole of the present invention and a foaming material.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following descriptions are of exemplary embodiments only, and are not intended to limit the scope, applicability or configuration of the invention in any way. Rather, the following description provides a convenient illustration for implementing exemplary embodiments of the invention. Various changes to the described embodiments may be made in the function and arrangement of the elements described without departing from the scope of the invention as set forth in the appended claims.

With reference to the drawings and in particular to FIG. 1, which shows a flowchart of a manufacturing method of environment-conservation shoe sole in accordance with the present invention, an environment-conservation shoe sole of the present invention is made of vegetable fibers, such as husks of rice and wheat, which is mixed with natural rubber and/or regular synthetic rubber and stirred together (11) to form a raw material (10) for shoe soles, wherein the fibrous component takes 5-25% of the raw material, the natural rubber 20-50%, and the synthetic rubber 25-55%. The raw material (10), after being added with additives (12) of 8-12% for facilitating curing and activation of molding, is sufficiently stirred (11) with suitable machinery, and then pressurized to form sheets of raw material or directly forming a bundle of sheets of the raw material (10) to allow for easy operation of subsequent trimming, collection, and management. The thickness of the raw material sheet can be varied as practically desired. The raw material sheet is then cut to a desired size and is quantitatively deposited into a forming mold to complete the step of feeding into the mold (13). Upper and lower molds are then clamped together to proceed with heating and pressurizing (14) for molding. The additive contained in the raw material (10) comprises sulfur that facilitates curing and prompter that facilitates activation of the rubber so that the material can be of enhanced flowability inside the mold and thus effectively and completely fills a cavity of the mold. This provides molding of completely-shaped shoe sole. The molding temperature is heated to a range between 100 to 160° C., which depends on the mixing ratio of the components of the raw material.

Depending upon the practical uses of the shoe sole, the mixing ratio of the components of the raw material (10) can be adjusted. A semi-product, after demolding (15), is finished with edge trimming (16) to remove burring and thus obtaining an integrally formed product of environment-conservation shoe sole (17).

To provide a shoe with different resiliency or flexibility, or to meet the requirements wearing-resistance for direct contact with solid ground and comfort of wearing, the ratio among different components of the raw material can be varied and/or further adding a filler (18) for variation of characteristics thereof to realize wearing-resistance and skidding-proof of the portion in contact with the ground. The addition of the filler (18) is within the range of 10-30%, and includes for example kaolin, calcium carbonate, glass powder, and aluminum oxide, of which the percentage can be adjusted in accordance practical requirement of solidification and toughness for realizing wearing-resistance and enhanced characteristics for use. In addition, a minor amount of foaming agent can be added in the raw material (10) to effect foaming of the raw material (10). This helps in reducing the weight of the final product and makes the shoe sole material more practical in use.

To provide variations of the shoe sole product, a surface sheet (20) that is manufactured in advance by pressurizing synthetic rubber into the form of sheet. The surface sheet (20) can then be stacked with the sheet of the raw material (10) in an inside-and-outside stacking manner or in a partially laminated manner, as shown in FIG. 2, which are then put in a mold for molding by heating and pressurizing to thereby form a shoe sole product having a surface of different characteristics or sharply distinct colors. Or, as shown in FIG. 3, the shoe sole sheet of the present invention can be combined with foaming rubber or PU material to carry out secondary filling and foaming and molding to form a shoe sole product of special purposes by comprising PU or foaming rubber. Since the composition of the raw material (10) of the shoe sole of the present invention is primarily rubber, in carrying out secondary molding with different foaming or PU material, or stacking with shoe sole layer (20), no additional adhering step is needed and the pre-formed sheet-like surface layer (20) and the raw material (10) can be together put in the forming mold for feeding into the mold (13) for simultaneously molding by simultaneously pressurizing and heating (14) to thereby obtain an integrated structure of shoe sole of special purposes. Additional operation is thus saved. In view of manufacturing of the shoe sole of special purposes, additional operation is saved, and non-separable stable integration can be provided. Consequently, novel environment-conservation rubber shoe sole that is economic and satisfies requirements of environment conservation is obtained. Due to the special combination of materials in accordance with the present invention, characteristics of use of the shoe sole material can be effectively enhanced and the overall costs of shoe sole manufacturing can be cut off at least 30% as compared to the regular shoe soles and can be even several times of reduction as compared to the currently-existing environment-conservation shoe soles.

It will be understood that each of the elements described above, or two or more together may also find a useful application in other types of methods differing from the type described above.

While certain novel features of this invention have been shown and described and are pointed out in the annexed claim, it is not intended to be limited to the details above, since it will be understood that various omissions, modifications, substitutions and changes in the forms and details of the device illustrated and in its operation can be made by those skilled in the art without departing in any way from the spirit of the present invention. 

1. A rubber shoe sole that is made with a process comprising steps of mixing and preparing raw material, feeding into a mold, molding, and edge trimming, the rubber shoe sole being characterized in that the raw material comprises fibrous components comprising rice/wheat husks having a percentage of 5-25%, natural rubber of 20-50%, synthetic rubber of 25-55%, and additives of 10-30%, the components of the raw material being mixed together and added with rubber curing additive and flowability-enhancing activation promoter, which takes a percentage of 8-12%, the mixture being subject to stirring and pressurizing to form a sheet of shoe sole material, which is then deposited in a forming mold for molding by heating and pressurizing to provide a semi-product that is removed out of the mold and subject to edge trimming to finally provide a shoe sole product.
 2. The rubber shoe sole as claimed in claim 1, wherein the additives selectively comprise kaolin, calcium carbonate, glass powder, and aluminum oxide.
 3. The rubber shoe sole as claimed in claim 1, wherein the sheet of raw material is deposited into the mold together with a pre-formed synthetic rubber surface layer to be heated and pressurized simultaneously for forming a shoe sole of different materials.
 4. The rubber shoe sole as claimed in claim 1 further comprising PU material or foaming rubber to carry out a secondary molding for forming a shoe sole of special purposes.
 5. The rubber shoe sole as claimed in claim 1, wherein the raw material is added with minor foaming agent to induce foaming of the shoe sole material. 